I posted the following elsewhere, but thought it may contribute to the conversation here:
I don't understand all of the arguements against a touch display for the iMac. The only one that makes sense to me is that it is a business decision for Apple to make based on the prospective market. For those of you saying that a large touch screen would cause fatigue I argue that a mouse and keyboard is far worse for you than any touch display could ever be. I have two friends that are graphic/web designers in their 20s with carpel tunnel already. I am a plumber by day and an audio engineer by night. In my day job I hold heavy tools and supplies at arms length all day long. At first it takes a toll on your body but you build up the stamina to withstand over time. Same would go for a touch screen iMac, in any position.
I would expect many of you are creative professionals. Have you seen this product?
http://www.wacom.com/en/Products/Cintiq/Cintiq24HD.aspx
If they can make money for the niche market, surely Apple can incorporate it into their already great product and profit from it.
Also, with Apple's commitment to those with disabilities (
http://www.apple.com/accessibility/ ), I am surprised they have not already made the iMac with a touch screen already. There are many instances where motor challenged individuals greatly benefit from the accessibility that a touch screen provides.
Just because EVERYONE won't benefit from a touch screen does not mean that there are not those who can. It all depends if Apple thinks they can do it cost efficiently.
Obviouslym the current UI is not 100% touch friendly. The UI needs to be tweeked to work with a touchscreen, but launching applications/programs works just as easily if not more easily with touch than it does with a mouse. Navigating files and folders may be the part that needs tweaking. After that it is the responsibility of the software developers to redesign their programs to be used with a touch interface. However, companies wouldn't adapt the programs for a market that doesn't exist, asking and paying hundreds of programmers to change their GUIs and functionalities. We have had touch interface windows PCs for quite sometime now, but that market is so segmented that most people wouldn't pay the premium for the touch screen. Most desktop Apple users, however, would be forced to buy a touchscreen if they came standard on the iMac. That would start the evolution of some of the software. I can see dozens of uses for touchscreen in Pro Tools already, AS-IS. I can only imagine the number of applications touch would be used for in CS.
As others are saying, a touchscreen iMac would not replace a keyboard and mouse, it would be used in conjunction with those input devices for those that could use it. I don't think it is coming with this update, but I hope it is coming with the next update.